• Title/Summary/Keyword: Activated carbon electrode

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Optimum Condition of Conducting Materials on Carbon-PTFE Electrode for Electric Double Layer Capacitor (EDLC용 Carbon-PTFE 전극에서의 도전재 조성 최적화)

  • 이선영;김익준;문성인
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.9
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    • pp.973-978
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    • 2004
  • This work describes the effect of conducting materials on the electrochemical performances of electric double layer capacitor. Three kinds of Carbon black, such as Acethylene Black, Super P Black, Ketjen black supplied by Denki Kagaku Kogyo, MMM Carbon, Ketjen Black International Co. respectively, was added in carbon-Polytetrafluoroethylene (PTFE) electrode, which composition is activated carbon : carbon black : PTFE = 80 : 15 : 5 wt.%, and were compared with their electrochemical properties. The electrode with Ketjen Black has showed the lowest resistance than other carbon black, and also exhibited the better rate capability between 0.5 mA/cm$^2$ ∼ 100 mA/cm$^2$ current density in unit cell capacitor. On the other hand, as increasing the composition of Ketjen Black, the specific resistances of electrodes were decreased and Ketjen Black content higher than 15 wt% increased. The best rate capability was obtained at the electrode with 15 wt.% of Ketjen Black in unit cell capacitor. This behaviors would be correlated with the dense structure of electrode.

Charge-discharge Characteristics of $TiO_2$-Activated Carbon Composite Electrode using Electrospinning (전기방사법으로부터 제조된 $TiO_2$ 섬유 복합전극의 충방전 특성)

  • An, Mi-Sun;Kim, Han-Joo;Son, Won-Keun;Takahashi, Hideaki;Park, Soo-Gil
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2022-2024
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    • 2005
  • Electrical double-layer capacitor (EDLC) is an electrochemical energy storage device in which electric charges only accumulated by a pure electrostatic attraction force are stored on the electrolyte-electrode interface in a form of double layer and separated by the electrolyte. The composite was prepared by mixing nanosize $TiO_2$ and activated carbon through a means of ultrasonic vibration in ethanol solution for 30 min in various mass ratios of $AC:TiO_2$ to form activated carbone-semiconducting oxide composites. Either 1.0 M $LiClO_4/EC-DEC$ or $Et_4NBF_4$/EC-DEC was used as the electrolyte. It was found that with modification of $TiO_2$, the specific capacitance of activated carbon measured at $1mA/cm^2$ was increased from 40 to 50 F/g. This method is unique in comparison the conventional method because it uses semiconducting TiO2 other than electrochemically active materials such as $RuO_2$. The increase in specific capacitance could be attributed to the decrease in electric polarization, caused by the introduction of $RuO_2$.

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Fabrication of Organic Electrolytes for Electric Double Layer Capacitor with Activated Carbon Cloth Electrode (활성탄소계 섬유포 전극을 이용한 전기이중층 커패시터용 유기 전해액의 제조)

  • 강안수
    • Journal of the Korea Safety Management & Science
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    • v.2 no.2
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    • pp.95-108
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    • 2000
  • Electrochemical charateristics of activated carbon fiber cloth(ACFC) electrode were studied with propylene carbonate(PC), ${\gamma}$-butyrolactone(GBL) and N,N-dimethyl-formamide(DMF) as a solvent and tetraethylammoniumtetrafluoroborate(TEABF$_4$), tetraethylammoniumhexafluorophosphate(TEABF$_{6}$), tetrabutylammoniumtetrafluoroborate(TBABF$_4$) and tetrabutylammonium hexafluorophosphate(TBAPF$_6$) as an electrolytes(active material). The concentrations of electrolytes were in the range of 0.2~1.2 N, the volume ratios of PC and DMF as a mixed solvent system, were 90:10, 80:20, 70:30, 60:40, 50:50, and 40:60 vol%. Electrochemical characteristics such as electric conductivity, internal resistance, and electric capacitance of fabricated unit cells were measured after the moisture of activated material was removed with molecular sieve. Electrochemical characteristics were better in mixed solvents system than in mono solvent system. The mono solvent system of 1.0 N electrolyte of GBL/TEABF$_4$ with activated carbon cloth electrodes showed better result but the mixed solvent system with PC and DMF/TEABF$_4$(50:50 vol%) and the concentration of 1.0 N electrolyte showed the best characteristics. Internal resistance was 3.47 $\Omega$ and specific capacitance was 19.1 F/g respectively.y.

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Carbon-free Polymer Air Electrode based on Highly Conductive PEDOT Micro-Particles for Li-O2 Batteries

  • Yoon, Seon Hye;Kim, Jin Young;Park, Yong Joon
    • Journal of Electrochemical Science and Technology
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    • v.9 no.3
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    • pp.220-228
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    • 2018
  • This study introduced a carbon-free electrode for $Li-O_2$ cells with the aim of suppressing the side reactions activated by carbon material. Micro-particles of poly(3,4-ethylenedioxythiophene) (PEDOT), a conducting polymer, were used as the base material for the air electrode of $Li-O_2$cells. The PEDOT micro-particles were treated with $H_2SO_4$ to improve their electronic conductivity, and LiBr and CsBr were used as the redox mediators to facilitate the dissociation of there action products in the electrode and reduce the over-potential of the $Li-O_2$ cells. The capacity of the electrode employing PEDOT micro-particles was significantly enhanced via $H_2SO_4$ treatment, which is attributed to the increased electronic conductivity. The considerable capacity enhancement and relatively low over-potential of the electrode employing $H_2SO_4$-treated PEDOT micro-particles indicate that the treated PEDOT micro-particles can act as reaction sites and provide storage space for the reaction products. The cyclic performance of the electrode employing $H_2SO_4$-treated PEDOT micro-particles was superior to that of a carbon electrode. The results of the Fourier-transform infrared spectroscopic analysis showed that the accumulation of residual reaction products during cycling was significantly reduced by introducing the carbon-free electrode based on $H_2SO_4$-treated PEDOT micro-particles, compared with that of the carbon electrode. The cycle life was improved owing to the effect of the redox mediators. The refore, the use of the carbon -free electrode combined with redox mediators could realize excellent cyclic performance and low over-potential simultaneously.

Electrochemical Characteristics of EDLC Fabricated by Different Preparation Processes of Activated Carbon Electrode (활성탄소 전극의 제조공정에 따른 EDLC의 전기화학적 특성)

  • Yang Chun-Mo;Kim H.J.;Cho W.I.;Cho B.W.;Yun K.S.;Rim Byung-O
    • Journal of the Korean Electrochemical Society
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    • v.4 no.3
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    • pp.98-103
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    • 2001
  • The electrochemical characteristics and specific capacitance were investigated by preparation processes (dip coating method, doctor blade coating method and paste rolling method) of activated carbon electrode for an EDLC(electric double layer capacitor). The EDLC using $LiPF_6$ salts and PC-DEC solvents showed good specific capacitance, 130F/g and small IR-drop at linear time-voltage curve. 0.11V, Cyclic voltammetry analysis using the activated carbon electrode prepared by dip coating method was shown closer to ideal EDLC characterization.

Development of Carbon Felt Electrode Using Urea for Vanadium Redox Flow Batteries (Urea를 이용한 바나듐 레독스 흐름 전지용 카본 펠트 전극 개발)

  • Kim, So Yeon;Kim, Hansung
    • Korean Chemical Engineering Research
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    • v.57 no.3
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    • pp.408-412
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    • 2019
  • In this study, nitrogen doped carbon felt was prepared by pyrolysis of urea at high temperature and applied as an electrode for vanadium redox flow cell. Urea is easier to handle than ammonia and forms $NH_2$ radicals at higher temperatures, creating a nitrogen functional group on the carbon surface and acting as an active site in the vanadium redox reaction. Therefore, the discharge capacity of activated carbon felt electrodes using urea was 14.9 Ah/L at a current density of $150mA/cm^2$, which is 23% and 187% higher than OGF and GF, respectively. These results show the possibility that activated carbon felt electrode using urea can be used as electrode material for redox flow battery.

A Hybrid Electrochemical Capacitor Using Aqueous Electrolyte (수용성 전해액을 사용하는 하이브리드 전기화학 축전기)

  • Kim, Jong-Huy;Jin, Chang-Soo;Shin, Kyoung-Hee;Lee, Mi-Jung
    • Journal of the Korean Electrochemical Society
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    • v.6 no.2
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    • pp.153-157
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    • 2003
  • A hybrid electrochemical capacitor having both characteristics of electric double layer capacitance and pseudo-capacitance was studied throughout cell tests. Asymmetric electrodes with $Ni(OH)_2/activated$ carbon based positive electrode and activated carbon based negative electrode were used in preparing test cells of $5\times5cm^2$. Cyclic voltammetry measurements and impedance measurements were conducted to understand electrochemical behavior of each electrode. To find an optimal mass ratio of negative to positive electrode, charge-discharge cycle tests were also performed.

Removal of Dust in Positive and Negative Plates of Electrode Coated with Activated Carbon (활성탄으로 코팅된 전극에서 분진의 제거)

  • Kim, Kwang Soo;Park, Hyun Chul;Jun, Tae Hwan;Lee, Ju Haeng;Nam, Sang Chul
    • Journal of Korean Society for Atmospheric Environment
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    • v.29 no.6
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    • pp.830-837
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    • 2013
  • The purposes of this research are to know the dust removal efficiency according to the changes of gab between positive and negative plates in dust removal chamber. The experiments for dust removal efficiencies were conducted with changing the electrode-plate gab from 2 cm to 1 cm while the electric pressure, influent flow, and linear velocity were kept 5 kV, 80 L/min, and 6 cm/sec, respectively. From the experimental results of the electrode-plate gab of 2 cm, dust removal efficiencies were decreased to as low as about 50%. Attached dust on the surface of electrodes was released due to a reverse electric charge of dust. From the experimental results of the electrode-plate gab of 1 cm, dust removal efficiencies were increased to as high as about 80% due to the dust attachment velocity to the electrodes to be far more fast than influent linear velocity. Finally, to protect a attached dust from occurring a reverse electric charge it is needed to install the non-conductor between positive and negative electrodes and also to remove air humidity.

Comparison of Electrochemical Properties of EDLCs using Activated Carbon Electrodes Fabricated with Various Binders (활성탄소 전극의 제조방식에 따른 EDLC 특성비교)

  • Yang, Sun-Hye;Jeon, Min-Je;Kim, Ick-Jun;Moon, Seong-In;Kim, Hyun-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.353-354
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    • 2006
  • This work describes the effect of binders, such as carboxymethylcellulose (CMC), CMC+Polytetrafluoroethylene (PTFE) and PTFE, on the electrochemical and mechanical properties of activated carbon-electrode for electric double layer capacitor. The cell capacitors using the electrode bound with binary binder composed of CMC and PTFE, especially m composition CMC ; PTFE = 60 : 40 wt %, has exhibited the better rate capability and the lower internal resistance than those of the cell capacitor with CMC. On the other hand, the sheet type electrode kneaded with PTFE was bonded with conductive adhesive on Al foil. This cell capacitor using the electrode with PTFE exhibited the best mechanical properties and rate capability compared to the CMC and CMC+PTFE one These behaviors could be explained by the well-developed network structure of PTFE fibrils during the kneading process.

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